기본을 넘어서: 효율적인 코딩을 위한 Python의 숨겨진 기능 익히기

x, y = 5, 10
x, y = y, x
print(x, y)  # Output: 10, 5

def greet(name, age):
    print(f"Hello, {name}! You are {age} years old.")

info = {"name": "Alice", "age": 30}
greet(**info)  # Output: Hello, Alice! You are 30 years old.

a, *b, c = [1, 2, 3, 4, 5]
print(a, b, c)  # Output: 1 [2, 3, 4] 5

squares = [x**2 for x in range(10) if x % 2 == 0]
print(squares)  # Output: [0, 4, 16, 36, 64]

matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
flat = [num for row in matrix for num in row]
print(flat)  # Output: [1, 2, 3, 4, 5, 6, 7, 8, 9]

from collections import defaultdict

d = defaultdict(int)
d['a'] += 1
print(d)  # Output: defaultdict(<class 'int'>, {'a': 1})

from collections import Counter

words = ["apple", "banana", "apple", "orange", "banana", "apple"]
count = Counter(words)
print(count)  # Output: Counter({'apple': 3, 'banana': 2, 'orange': 1})

from collections import deque

queue = deque([1, 2, 3])
queue.append(4)
queue.popleft()
print(queue)  # Output: deque([2, 3, 4])

class Lazy:
    def __init__(self):
        self.data = {}

    def __getattr__(self, name):
        if name not in self.data:
            self.data[name] = f"Value for {name}"
        return self.data[name]

obj = Lazy()
print(obj.foo)  # Output: Value for foo

def infinite_counter():
    count = 0
    while True:
        yield count
        count += 1

counter = infinite_counter()
print(next(counter))  # Output: 0
print(next(counter))  # Output: 1

def numbers():
    for i in range(10):
        yield i

def squared(seq):
    for num in seq:
        yield num**2

pipeline = squared(numbers())
print(list(pipeline))  # Output: [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]